Range outlet

Heres the story. Have a rental house and tenant said that the stove breaker was tripping in the panel box when used the oven.
She supplies her own stove and she said she bought a new whirlpool one and it does the same thing as her old one. If I believe her sheâ€™s said she had it checked and the service person said it was not a problem with the range. When the oven is turned on it trips the breaker.
I went over to the house. Checked the range outlet just to be sure the terminal screws were tight. Panel box only 5 years old but had a 40-amp range breaker. I replaced the 40-amp breaker with a 50 amp since it had 8-2 gauge romex. And my breaker does not trip. I wish I had turned on the oven first to confirm it did trip the old breaker like tenant said, but I did not.
After replacing I then went and checked the range. All 4 surface burners will come on and work. Display with clock will work but if you try and turn on the oven the display will show â€œP5Hâ€ for a few seconds then the display with clock goes completely blank and oven does not come on.
I did a goggle search about this P5H code and the only answer that I could find was that it could be a problem with the range outlet ground.
Breaker at least now does not trip and I read 120 x 2 volts at outlet. Black lead to center slot and my red meter lead to each of the other slots and got 120V at each one. Its only the 3 wire outlet. Also all 4 surface burners work OK.

But is it possiable it is not a problem with the range. I mean can I be sure that it is not a problem with the panel box?

New ranges have the neutral and ground coming in as separate leads. With a 3-wire (hot, hot, ground), you need to follow the instructions with the range to bond the ground and neutral properly to get everything to work well.

50A on 8 gauge only if it is copper. Make sure its copper. I'm with you and don't buy the range tripping the CB story based on the fact the oven won't power up after swapping the breakers. Also, most standard stoves should use a 40A, not a 50A breaker. I would back down to the 40A even if the house wiring can handle it unless the nameplate on the range says 50A.

For 3 wire outlets the ground and neutral need to be tied together inside the range. If it is a new range the installation manual should have steps showing how to do this. Since most newer ovens use electronic circuits its quite possible it is sensing that the range is not grounded and therefore refusing to power up. You could call Whirlpool and they could probably clear that up.

Also did you get 240+- volts between the two slotted pins on the receptacle? Ranges are generally a 240V device with the 120V legs just used to power the electronics, and oven light. Seeing that the burners work its probably safe to say you have 240V.

So you can now assume that your breaker was fine to begin with and now that you swapped it out it may be over sized for both the wiring and the range, however the problem with the oven is most likely related to the oven itself not being wired properly (ground not tied to neutral) for a 3 prong outlet.

Check the legalities of doing DIY wiring on rental properties in your area. In many areas you must call an electrician.

You need to measure the amperage draw on the stove and/or test it with a known good 40A breaker installed before ruling out problems with your panel.

What's the nameplate rating on the stove? If it's designed for a 40A circuit, you must use a 40A breaker; if it's designed for a 50A circuit, you must use a 50A breaker. If it's designed for a 40A circuit but regularly trips a known good 40A breaker (or draws more than 40A), then there's something dangerously wrong with the stove or your wiring.